Pterosin compounds are sesquiterpenoids existed in Bracken. Some members of this family are found to possess antineoplastic activity as previously described in, for example, Japan Pat. No. 63146839A2, Chem. Pharm. Bull. 1978, 26, 2346, Molecules 2008, 13, 255.
Diabetes, a disorder of sugar metabolism, is characterized by abnormally high blood glucose levels. There are two different types of diabetes, namely the non-insulin-dependent or maturity onset form, also known as type 2; and the insulin-dependent or juvenile onset form, also known as type 1.
Type 2 diabetes usually occurs in adults and is highly associated with obesity. Type 2 diabetic patients must control their diet and are encouraged to lose weight and to exercise. They take medicine that increase insulin sensitivity or stimulate the pancreas to release insulin. Current drugs for type 2 diabetes include sulfonylureas, meglitinides, biguanides, thiazolinediones, and α-glycosidase inhibitors, which however have a number of limitations, such as adverse effects and high rates of secondary failure. In contrast, type 1 diabetic patients are not over-weight relative to their age and height, and exhibit a rapid onset of the disease at an early age. Type 1 diabetic patients must administer insulin by injection for their entire life time. Although there has been much research on oral administration of insulin, no successful oral dosage of insulin is marketed at present.
As a result, there remains a need for alternative drugs for treatment of diabetes (type I and type II) and obesity which preferably have fewer advertise effects and can be orally administered.